如何使用javas Process.waitFor（）？

本文介绍了如何使用javas Process.waitFor（）？的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我正在尝试从Java运行命令行命令，快速的健全性检查让我意识到我遇到麻烦的原因是我无法获得 pr.waitFor（）请致电以下工作。这个程序在不到30秒后结束，并且在foo：之后不打印任何内容。我预计它需要超过30秒并在foo：之后打印一个随机数。我究竟做错了什么？

I am trying to run command line commands from Java and a quick sanity check made me realize that the reason I am having trouble is that I can't get the pr.waitFor() call below to work. This programs ends in less than 30s and prints nothing after "foo:". I expected it to take just over 30 s and print a random number after "foo:". What am I doing wrong?

import java.io.BufferedReader; import java.io.InputStreamReader; public class Sample { public static void main(String[] args) throws Exception { Runtime rt = Runtime.getRuntime(); Process pr = rt.exec("sleep 32; echo $RANDOM"); pr.waitFor(); BufferedReader input = new BufferedReader( new InputStreamReader(pr.getInputStream())); String line=null; StringBuilder s = new StringBuilder(); while((line=input.readLine()) != null) { System.out.println(s); s.append(line); } System.out.println("foo: " + s.toString()); } }

推荐答案

你应该尝试这个：

Process pr = rt.exec(new String[]{ "bash","-c", "sleep 32; echo $RANDOM" });

这将启动一个shell进程，然后在shell中运行你的命令。在命令完成之后，shell才会返回。

This launches a shell process and then within the shell runs your commands. The shell doesn't return till AFTER the commands have completed.

请告诉我这是否适合您。

Let me know if that works for you.